1. Field of the Invention
This invention relates generally to gateway devices and architectures used with signaling frameworks for maintaining session characteristics between two clients, e.g., as used with an instant messaging application or Voice over IP (VoIP) application.
2. Related Art
Many applications utilize signaling frameworks for tracking and maintaining session characteristics between two clients. One illustrative example includes instant messaging applications. Instant messaging applications generally enable two or more participants to communicate over a computer network, such as the Internet or an internet (e.g., a private network), in more or less real time. Typically, each participant uses a client computer system to send and receive messages (including, e.g., text, voice, files, and the like) via a user interface. Each client computer in communication is connected via a network to a common instant messaging service provider and connection server. The connection server receives and processes messages from participants, including by forwarding them to the client systems of the other participants for display. The connection server may also be configured to send messages on behalf of the system, such as to inform participants that a fellow participant has disconnected or logged off.
Typically, instant messaging application software is installed at each client system to enable the client system to be used as an instant messaging client. The instant messaging software may be made available for download, for example, from a web page accessible via the Internet. A user invokes this software on the client system in order to communicate by instant messaging with one or more other participants. The client side application software typically establishes a connection between the client system and the connection server and either automatically logs the user into the connection server or prompts the user to enter the information necessary to log in, such as a user name and password. The user may then communicate by means of instant messaging with one or more other users of the instant messaging system. There are several known instant messaging systems and service providers, such as MSN® Messenger, Yahoo!® Messenger, AOL® Instant Messenger (“AIM”), and the like.
Generally, a service provider comprises a plurality of gateway devices for validating and routing traffic between clients (and between service provider networks). For example, a service provider network may include gateway devices for receiving and communicating signaling events to and from their native protocol to a common protocol such as SIP. Such gateway devices are stateful, e.g., monitoring details of the dialogs (i.e., the interactions/exchanges of information between communication computers such as responses and requests). For example, with respect to an instant messaging application, a gateway device stores subscription and presence indicators according to buddy list information and the like, extinguishes dialogs, and so on. If a gateway device fails to function correctly (e.g., the gateway device crashes) the dialog information (e.g., details such as subscription and presence indicators) may be lost, causing disruption in the functionality and operation of the communications. This is particularly an issue with applications having long lived dialogs as typically with instant messaging applications, however, such problems are also issues for other applications such as VoIP and others.